An adhesive patch usually includes a support made of a woven fabric, a nonwoven fabric, or the like, a pressure-sensitive adhesive agent layer provided on one surface of the support, and a release sheet which is releasably attached to the pressure-sensitive adhesive agent layer. Further, a percutaneously absorbable drug and the like are contained in the pressure-sensitive adhesive agent forming the pressure-sensitive adhesive agent layer.
With respect to such an adhesive patch, ease in applying to the skin has been always required. Therefore, conventionally, adhesive patches as described, for example, in the following Patent Literatures 1 to 4 have been proposed.
The adhesive patches described in Patent Literatures 1 and 2 include a support having stretching properties and a release sheet releasably attached to a pressure-sensitive adhesive agent layer on the support, and a perforated line is formed in the central portion of the release sheet. At the time of using this adhesive patch, first, the adhesive patch is pulled to the right and left to rip the perforated line apart, to expose the pressure-sensitive adhesive agent layer. Then, the exposed portion is applied to the skin, and thereafter, the release sheet is removed.
Further, the adhesive patch described in Patent Literature 3 is an adhesive patch in which two release sheets are placed on a pressure-sensitive adhesive agent layer, and an inner end of one of the release sheets is folded, and an inner end of the other release sheet is superposed on the folded portion. In such an adhesive patch, because it is possible to pinch the folded portion or the end superposed thereon, it is possible to easily remove the release sheets from the pressure-sensitive adhesive agent layer, thereby easily applying to the skin.
Moreover, the adhesive patch described in Patent Literature 4 is an adhesive patch in which two release sheets are placed on a pressure-sensitive adhesive agent layer in a state in which the two release sheets are respectively folded so as to butt against each other with their folded lines. In this adhesive patch as well, in the same way as the adhesive patch described in Patent Literature 3, it is possible to pinch the folded portion to easily release the release sheets from the pressure-sensitive adhesive agent layer.
Further, the adhesive patch described in Patent Literature 5 is a wound dressing, that is a so-called adhesive plaster, which is different from an adhesive patch, and this is an adhesive patch which is designed for easily releasing of the release sheet. That is, this wound dressing is formed, in the same way as the adhesive patch described in Patent Literature 4, such that two release sheets are placed on a pressure-sensitive adhesive agent layer in a state in which the ends of the two release sheets butt against each other. Then, pull-tabs for pulling the release sheets to release the release sheets are adhered to the ends on the butting sides of the respective release sheets. In this wound dressing configured in this way as well, in the same way as the ones described in Patent Literatures 3 and 4, it is possible to pinch the pull-tabs to easily release the release sheets from the pressure-sensitive adhesive agent layer.
The above-described conventional adhesive patches and wound dressing are respectively improved in ease of application. However, in the adhesive patches described in Patent Literatures 1 and 2, when the exposed portion of the pressure-sensitive adhesive agent layer is applied to the skin after dividing the release sheet along the perforated line, it may be difficult to release the release sheet in some cases.
On the other hand, with respect to the adhesive patches described in Patent Literatures 3 and 4 and the wound dressing described in Patent Literature 5, there is the advantage that it is easy to release the release sheets from the pressure-sensitive adhesive agent layer because there are portions to be pinched. However, there is a problem that medicinal properties in the pressure-sensitive adhesive agent layer leak out of the superposed portion or the butting portion of the two release sheets.
Further, with respect to the adhesive patch described in Patent Literature 3, because the folded portion in the one of the release sheets and the end of the other release sheet superposed thereon are directed in the same direction, it is configured to be able to pinch the release sheet only from one side, which is inconvenient. Moreover, a special sheet folding device is required in order to fold the release sheets, which also brings about the problem of an increase in the cost of manufacturing the adhesive patch.
Also, with respect to the adhesive patch described in Patent Literature 4, a process of folding the release sheets during the manufacture thereof is necessary, and moreover, it is necessary to accurately butt the folding lines of the two release sheets in order to suppress leakage of the medicinal properties as low as possible, which makes it extremely difficult to manufacture the adhesive patch.
Further, with respect to the configuration described in Patent Literature 5, in the same way as the adhesive patch described in Patent Literature 4, it is necessary to accurately butt the release sheets and the pull-tabs. Further, even when the sheet material and the tab material are cut after the pull-tabs (tab material) before cutting are adhered to the release sheets (sheet material) before cutting, there is a problem that the portion with high strength at which both are adhered to one another is to be cut, and therefore, it is difficult to cut it.
Further, with respect to the wound dressing described in Patent Literature 5, because release sheets are separated with little resistance at the time of pulling the pull-tabs to release the release sheets, anti-releasing means for preventing releasing of the release sheets are provided at the edges of the wound dressing. Meanwhile, the manufacturing process increases one process or more by providing the anti-releasing means, which brings about the problem of requiring time and cost for manufacture. Further, as the anti-releasing means, there is a folding type (refer to FIG. 5 in Patent Literature 5) or a clip type (refer to FIG. 6 in Patent Literature 5). However, with these types, projecting portions are formed on the surface of the wound dressing, which may hinder applying it to an affected area. Therefore, such projecting portions are unsuitable for a large-size wound dressing such as a poultice or a plaster.
Furthermore, with respect to the configurations described in Patent Literatures 3 to 5, because the two release sheets are not combined, both may have a position gap, or may be turned up, and the medicinal properties easily leak out in such a case, which leads to the problem in view of stability in drug formulation. Further, a position gap between the release sheets deforms the support at the time of pulling the folded portions or the pull-tabs, which may bring about a problem of wrinkling at the time of application. Such a harmful effect due to a position gap becomes apparent in particular in the configurations described in Patent Literatures 4 and 5 in which the ends are merely brought to butt against each other.
As described above, there are various problems in the conventional technologies. Therefore, an adhesive patch which is easily applied to the skin and its manufacture is easy has been demanded.